The Adapter for EF Mount Lens to Sony E-Mount Camera from Novoflex attaches an EF lens with its own built-in aperture control ring to a Sony E-mount camera for expanded versatility with your NEX (E-mount) camera. This adapter is designed for EF mount lenses that utilize their own aperture control ring such as Canon and Zeiss cine lenses and third party SLR EF mount lenses such as those by Samyang, Rokinon and Bower. Canon EF SLR mount lenses that do not have a built-in aperture control ring are not compatible. his is a manual adapter and therefore offers no electronic communication between camera and lens. Infinity focus is maintained by the lens and its durable build is made for long term, professional use. It is compatible with Sony full frame E-mount cameras.